Unanswered Questions
206 questions with no upvoted or accepted answers
12
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0
answers
134
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Active improving of nanodiamond surfaces for NV centers?
This question is related (and complementary) to "Passive improving of nanodiamond surfaces for NV centers?".
Nitrogen-Vacancy centers (NVs) have astonishing quantum properties, which make them ...
glS♦
- 26.9k
8
votes
0
answers
295
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What is a gate-level circuit used in the 2022 Jafferis et al. experiment on Sycamore?
A recently published Nature paper of Jafferis et al. describes an experiment with a handful of qubits performed on Google's Sycamore processor to explore the SYK model in the context of AdS/CFT and ...
- 14.4k
8
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0
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136
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Qubit fidelity of DWAVE device
Since DWAVE quantum device is constructed using superconducting flux qubits, each qubit cannot be produced identically so that the fidelity of the qubit must be different. DWAVE only provides the ...
- 397
8
votes
2
answers
749
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What design considerations set the frequency bounds for superconducting qubits?
Superconducting qubits generally have frequencies within the range of 4 - 8 GHz. What design considerations give the upper and lower bounds for what is a feasible design. I.e, why can't they be higher ...
CommunityBot
- 1
8
votes
0
answers
319
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What are the main obstacles to overcome to build silicon-photonic quantum computers?
In superconducting quantum computers, we use mostly superconducting qubits or trapped ions. However, those systems are quite large because their environment either requires near absolute zero ...
- 17.8k
8
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0
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382
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In D-Wave's universal quantum computer, why does the YY term have to be driven along with the linear X term?
D-Wave has a new prototype annealer that uses a Hamiltonian which, if there was enough qubits and sufficient control, would be able to simulate any universal circuit-based quantum computer with at ...
6
votes
0
answers
143
views
How are Toffoli and a basis-changing single-qubit gate universal?
The Toffoli and Hadamard gates are universal for quantum computing: you can approximate any unitary up to arbitrary precision with a circuit built from these two gates. This is proved for example by ...
- 161
6
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0
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132
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Writing circuits in Qiskit using only Clifford and T gates
Is there a way in Qiskit to write my circuit using only Clifford and T gates (CX, S, H, T and I think also $S^\dagger$ and $T^\dagger$)? With the function compile (with aer simulator) it gives me some ...
- 3,469
5
votes
0
answers
89
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Is circuit cutting equivalent in anyway to quantum teleportation?
I've been introduced recently to circuit cutting, and after seeing the 4 orthogonal measurements with their 8 corresponding initializations but no initial transfer of classical info, the first thing ...
5
votes
0
answers
88
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What is the computational complexity of decomposing operators in terms of quantum gates?
I have recently worked on a problem involving a rather large Hamiltonian, which I wrote some Python code for its generation following the method in this paper.
No when I used qiskits ...
- 51
5
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0
answers
59
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Is there a convention in quantum circuit diagrams for specific quantum measurements?
Is there a convention in quantum circuit diagrams for specific quantum measurements? For example, how could one express the measurement $|0\rangle \langle 0|$ in a circuit diagram?
glS♦
- 26.9k
5
votes
0
answers
853
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What exactly is the "quantum singular value decomposition"?
I know what is singular value decomposition, meaning given a matrix and write it as multiplication three different matrices, and middle matrix being diagonal and entries are singular values. So, what ...
glS♦
- 26.9k
5
votes
2
answers
215
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What is the shortest-circuit-depth quantum-benchmarking algorithm?
An algorithm implementing a model whose results are known, and from the known results, the benchmarking of the device could be done. What is the currently known shortest circuit depth algorithm that ...
CommunityBot
- 1
5
votes
0
answers
188
views
How do we realise photonic gates?
I am interested in photonic computing, and I am curious how the gates work. I once saw a picture of a photonic CNOT gate that used just mirrors and polarizers. I have not been able to find any ...
glS♦
- 26.9k
5
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0
answers
94
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Are single photons necessary for this quantum autoencoder implementation?
The following diagram is from Experimental Realization of a Quantum Autoencoder: The Compression of Qutrits via Machine Learning
How this setup works:
What will be obtained from this set up is the ...
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